Hi Tom,

> -----Original Message-----
> From: Tom Herbert [mailto:[email protected]]
> Sent: Thursday, April 30, 2015 1:09 PM
> To: Templin, Fred L
> Cc: Lucy yong; [email protected]; [email protected]
> Subject: Re: [Int-area] Why combine IP-in-UDP with GUE?
> 
> On Wed, Apr 29, 2015 at 10:20 AM, Templin, Fred L
> <[email protected]> wrote:
> > Hi Tom,
> >
> >> -----Original Message-----
> >> From: Tom Herbert [mailto:[email protected]]
> >> Sent: Wednesday, April 29, 2015 10:13 AM
> >> To: Templin, Fred L
> >> Cc: Lucy yong; [email protected]; [email protected]
> >> Subject: Re: [Int-area] Why combine IP-in-UDP with GUE?
> >>
> >> On Wed, Apr 29, 2015 at 9:28 AM, Templin, Fred L
> >> <[email protected]> wrote:
> >> > Hi Tom,
> >> >
> >> >> -----Original Message-----
> >> >> From: Tom Herbert [mailto:[email protected]]
> >> >> Sent: Wednesday, April 29, 2015 9:00 AM
> >> >> To: Templin, Fred L
> >> >> Cc: Lucy yong; [email protected]; [email protected]
> >> >> Subject: Re: [Int-area] Why combine IP-in-UDP with GUE?
> >> >>
> >> >> On Wed, Apr 29, 2015 at 7:50 AM, Templin, Fred L
> >> >> <[email protected]> wrote:
> >> >> > Hi Lucy,
> >> >> >
> >> >> >> -----Original Message-----
> >> >> >> From: Lucy yong [mailto:[email protected]]
> >> >> >> Sent: Wednesday, April 29, 2015 7:48 AM
> >> >> >> To: Templin, Fred L; [email protected]; [email protected]
> >> >> >> Subject: RE: [Int-area] Why combine IP-in-UDP with GUE?
> >> >> >>
> >> >> >>
> >> >> >> Getting back to our earlier discussion, IP-in-UDP and GUE are 
> >> >> >> currently two half-solutions. Put them together and you get a
> >> whole
> >> >> >> solution.
> >> >> >> Keep them apart, and someone else is going to have to write a whole 
> >> >> >> solution sometime down the line from now.
> >> >> >> [Lucy] GUE can support IP payload. Don't know why you state that 
> >> >> >> they are two half-solutions. Is the compression a
> mandatory
> >> >> >> requirement here? I think that IP-in-UDP proposal as a compression 
> >> >> >> version is better that use of first nibble. However we
> need
> >> >> clarify
> >> >> >> what limitation and constraint the compression solution has.
> >> >> >
> >> >> > GUE is missing header compression, and IP-in-UDP is missing tunnel
> >> >> > fragmentation. That is what I mean when I say that if combined you
> >> >> > get a whole solution.
> >> >> >
> >> >> Adding this header compression just adds a whole bunch of complexity
> >> >
> >> > The only additional requirement is to check the first nibble of the
> >> > UDP-encapsulated payload.
> >> >
> >> >> to the protocol to save a grand total of four bytes for what is likely
> >> >> a very narrow use case. This is not applicable when GUE is used for
> >> >> network virtualization, we are encapsulating something other than IP,
> >> >> we need OAM, or using any other feature of GUE. In my deployment, I
> >> >> don't have any use case for that since minimally I will be using
> >> >> remote checksum offload option because that does give a material
> >> >> performance advantage.
> >> >
> >> > What you have just done is spelled out specific use cases that
> >> > require special-purpose solutions - that is not "generic".
> >> >
> >> >> The premise of GUE is simple, it has a simple header that encapsulates
> >> >> any IP protocol expressed by IP protocol number and allows optional
> >> >> extensions and control packets-- let's keep it simple! If saving those
> >> >> four bytes is really important in some deployment and GUE is still
> >> >> needed in certain case, then just use GUE and IP-in-UDP in tandem.
> >> >
> >> > That would require two different UDP port numbers as opposed to
> >> > checking the first nibble, which there was some earlier discussion
> >> > about. If you want to call something "generic", then why not make it
> >> > truly generic?
> >> >
> >>
> >> It already is generic. Encapsulation of IPv4 and IPv6 is already
> >> implemented and deployed. Including this optimization does not make
> >> the protocol more generic.
> >
> > If it is deployed before the document is published as an RFC, then
> > the deployed base would have to be updated to match the eventual
> > RFC anyway.
> >
> >> Anyway, if you want to proceed with this please provide a specific
> >> proposal on how do to it.
> >
> > Change the GUE header to treat the first nibble as a next header
> > selector. 4 means IPv4, 6 means IPv6 and X means GUE.
> >
> Okay, thinking about this some more, I suppose we can actually support
> direct IP encapsulation just by defining GUE version 0x1 to be direct
> IP encapsulation. eg. 01 indicates IP encapsulation, 0100 0110 are
> IPv4 and IPv6. This burns one version number and requires a subtle
> change in the GUE draft to make it clear that the GUE version defines
> defines everything after it, but it is forward compatible and doesn't
> impact real GUE.

If you can do this, please sign up AERO as a committed GUE user.

Thanks - Fred
[email protected]

> > Thanks - Fred
> > [email protected]
> >
> >> Tom
> >>
> >> > Thanks - Fred
> >> > [email protected]
> >> >
> >> >> Tom
> >> >>
> >> >> > Thanks - Fred
> >> >> > [email protected]
> >> >> >
> >> >> >> Lucy
> >> >> >>
> >> >> >> Thanks - Fred
> >> >> >> [email protected]
> >> >> >>
> >> >> >> > However, if GUE payload is
> >> >> >> > IP, it is OK to inspect the first nibble of the payload to 
> >> >> >> > determine IPv4 or IPv6 because this aligns with IP protocol.
> >> >> >> >
> >> >> >> > Thanks,
> >> >> >> > Lucy
> >> >> >> >
> >> >> >> > - Stewart
> >> >> >> >
> >> >> >> >
> >> >> >> >
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